Seat support structures for vehicle seats and the like must be sturdy and substantial structures that are capable of supporting the seat and its occupants during normal usage as well as under severe conditions that might impose extraordinary loads on the structure as would be the case during violent or abrupt maneuvering of the vehicle or in the event of an accident or crash. Moreover, as is often the case, a majority of vehicle seats accommodate two, three or more occupants and are supported by a structure that is common to all of the adjacent seat places in a single row so that an adequate structure that has the capability of supporting such a multiple seating arrangement and its occupants, must of necessity possess sufficient strength to absorb all of the stresses exerted on the structure during normal as well as emergency conditions throughout its service life. Consequently, when the normal safety margins are incorporated, such seat support structures tend to be relatively heavy substantial structures with considerable bulk and/or a complex network of struts and similar stress absorbing members.
Consequently, it is not unusual for the structure or some of its members to encroach upon the under seat space available for leg and foot room for the seat occupants in the preceding seats when the seats are arranged in rows as in most vehicles.
As is well known in aircraft seating arrangements, the underseat area is normally utilized to accommodate carry-on parcels such as overnight bags, brief-cases, purses and the like and any incursions by the seat structure upon the space that would otherwise be available for these purposes constitutes a great inconvenience to the passengers. Moreover, the aircraft owner/operators are never favorably disposed toward such structures that could discourage patronage.
Furthermore, it can be readily appreciated that in aircraft seat support structures, any unnecessary weight associated with the seat structures has a deleterious and domino effect on the aircraft's performance in a variety of ways not the least of which is a notable reduction in the aircraft's payload capability and operational profitability.
In addition, most aircraft as well as a number of other types of vehicles are provided with seat securing tracks constructed in the floor and made integral with the vehicle structure so that seating loads are transmitted to the primary aircraft structure. Obviously since each aircraft type varies in design and structure, the seat track locations can vary according to the type and model of aircraft. As a consequence, many aircraft seats must either be designed to accommodate a particular type or model of aircraft, or incorporate some means of accommodating the variations encountered in the seat track locations in different types of aircraft and vehicles. Frequently, attempts to increase the versatility of the seat structures in this regard results in added complexity and weight of the seat support structure.